Relationship between portal vein pressure and liver regeneration after portal branch ligation in rats / 中华消化外科杂志

ABSTRACT

Objective To investigate the relationship between portal vein pressure and liver regeneration after 90% portal branch ligation in rats.Methods Forty-five male SD rats underwent 90% portal branch ligation (including 5 rats underwent sham operation),and then the changes of portal vein pressure and weight of unligated hepatic lobes were detected.The morphological changes of hepatocytes of the unligated hepatic lobes were observed under a light microscope.Proliferative cell nuclear antigen(PCNA)index was detected by immunohistochemistry,and hepatocyte apoptosis of the unligated hepatic lobes by TUNEL method.All data were analyzed by Pearson rank correlation analysis and t test.Results Thirty-eight out of 40 rats survived(95%).The ligated hepatic lobes diminished progressively,whereas the unligated hepatic lobes regenerated.Preoperative portal vein pressure was(9.1±1.8)cm H_2O(1 cm H_2O=0.098 kPa),and it was increased significantly shortly after the ligation and reached (15.8±2.7)cm H_2O 12 hours later(t=6.847,P＜0.05).The portal vein pressure decreased from(13.6±2.3)cm H_2O at day 1 to(9.3±2.0)cm H_2O at day 28.Preoperative positive PCNA index was 7%±3%,which was significantly lower than 14%±5%at postoperative 12 hours,21%±6%at day 3 and 26%±7%at day 5(t=9.129,P＜0.05),and it began to return to normal at day 5.Few apoptotic hepatoeytes were observed in preoperative liver tissue and unligated hepatic lobes.The expression of PCNA in unligated hepatic lobes and portal vein pressure had apositive correlation at postoperative day 1,3,5(r=0.913,0.896,0.908,P<0.05)and a negative correlation at postoperative day 14(r=-0.926,P<0.05).Conclusions The regeneration of hepatocytes in unligated hepatic lobes is activated after 90% portal branch ligation,and the regenerated liver compensates the weight loss of the ligated hepatic lobes.Liver is regenerated mainly by speeding hepatocyte proliferation rather than reducing hepatocyte apoptosis.Changes of portal vein pressure may play an important role in liver regeneration.